Do extensive, "known" conworld metaphysics correlate with IRL belief?

Another post made me wonder if the desire to give our worlds solid answers to big questions (afterlife, gods, definite creation myths) correlates with IRL belief that we've got it figured it out. Or conversely, that someone who feels such questions are either unanswerable, unknown or self-evidently silly won't particularly enjoy giving their world a solid framework in these aspects.

Thoughts, perspectives, alternatives in the comments.